A country which wields such economic or military power, it can dominate any other. The USA and the USSR were two major superpowers until the collapse of the USSR. The USA is now the world's only superpower. However, China is quickly rising to become a superpower, especially with the recent launch into the space race, and the EU has the potential to develop into the world's most powerful superpower. Former superpowers include Britain, Spain, The Roman Empire and France. Nazi Germany and Japan were arguably superpowers during WWII.